In an ideal world, every inventor would come to us with a high-quality, fully functional, beautifully decorated prototype. But this is not an ideal world. You're much better off having your item reviewed in the rough development stages to avoid investing a lot of effort into something that is likely to be changed, or worse, something that is not viable at all.
Depending on the item you have created, we can, and do, work with pictures, videotape, drawings, even written descriptions. Just decide what is appropriate for your situation, and keep in mind that shipping can lead to damage or loss of your materials.
If you have a game, send a copy of the board and a clear set of rules. If you have a toy, but the prototype is large, delicate or irreplaceable, send a videotape or photographs. If you just have an idea, write out its description and how it works.
Unlike most people, we try to see the potential in your item without becoming stuck on the quality of the prototype. Send what you can; if we need more we'll call.